"The scientific fine print in the advisory committee's report makes it clear that Americans should be eating much less saturated fat, trans fat, cholesterol and added sugars," said Margo G. Wootan, director of nutrition policy at the Center for Science in the Public Interest, who signed the letter. "But the committee's proposed take-home messages don't provide clear-cut advice on improving diets. It's not enough just to say 'choose wisely' when we know we're eating too much of some foods and not enough of others."

In their letter, the nutrition experts said better advice on fats would be: "Eat less cheese, beef, pork, whole and 2% milk, egg yolks, pastries and other foods that are high in saturated fat, trans fat or cholesterol."

Likewise, they suggested that the main carbohydrate message should be: "Drink fewer soft drinks and limit cake, cookies, frozen desserts and other foods rich in refined sugars."

The nutrition experts urged HHS and USDA to conduct a series of focus groups to assess how their suggestions and others could be refined to best motivate Americans to improve their diets. They noted that given the limited budgets the two departments have to promote the guidelines, easy-to-understand messages were especially important.

Other signatories to the letter included Marion Nestle from New York University, David Katz from Yale University School of Medicine, John La Rosa from SUNY Downstate Medical Center, Thomas N. Richardson from Stanford University School of Medicine and Carlos A. Camargo of Harvard Medical School, a member of the 2005 Dietary Guidelines Advisory Committee.